The crawler-transporter moves Space Shuttle Atlantis on its rollback to the Vehicle Assembly Building.

On Launch Pad 39B, the crawler-transporter moves Space Shuttle Atlantis along the ramp and away from the rotating and fixed service structures, at right, on its rollback to the Vehicle Assembly Building. First motion off the pad was at 10:04 a.m. EDT. The crawler is 131 feet long, 113 feet wide and 20 feet high. It weights 5.5 million pounds unloaded. The combined weight of crawler, mobile launcher platform and a space shuttle is 12 million pounds. Unloaded, the crawler moves at 2 mph. Loaded, the snail's pace slows to 1 mph. The rollback is a safety precaution as the area waits for the arrival of Tropical Storm Ernesto. The storm is forecast to be bringing 58-mph to 70-mph winds in the next 24 hours. The shuttle will be moved into high bay 2, on the southwest side of the VAB, for protection from the storm. Photo credit: NASA/Ken Thornsley